This invention relates generally to a control system for use with a fabric washing machine and in particular to a control system for checking the operability of a control switch in a fabric washing machine where the timer is not manually advanced through any part of its cycle of operations.
In the operation of both domestic and commercial fabric washing machines and fabric drying machines, it has been generally common practice for those machines with electromechanical timers to provide a timer knob extending forwardly through the control panel. The timer knob can be manually operated by the machine user to position the timer at a cycle start posture or to advance the timer through a particular portion of a cycle of operations.
Some commercial machines such as Low, U.S. Pat. No. 3,111,830, show a clothes washing machine without a protruding timer knob wherein the entire machine is shut down when the lid is opened at the start of or during wash spin and only the drive motor is shut down as the lid is opened during rinse spin allowing the timer motor to run through the cycle. Subsequent operation of the coin slide initiates a new timing cycle by indexing the timer cams to the start position. Further, Jarvis, U.S. Pat. No. 3,122,009, provides a safety interlock control system which assures that when the access door to the wash basket is opened before the end of a cycle, the basket will be stopped but the timer device will time out to the end of a normal cycle. The timing out will occur without causing any of the remaining cycle operations to occur. The machine is then conditioned for a new cycle of operation by the insertion of a predetermined number of coins. While these prior art machines provide for timing out to the end of a cycle if the lid is prematurely opened, there is no provision for checking the operability of a lid actuated switch and automatically conditioning the timer for initiating a new cycle of operations after confirming the operability of the lid actuated switch and preventing the conditioning if the lid actuated switch is failed.
Ellingson et al, in U.S. Pat. No. 4,510,777, disclose a washing machine having a microcontroller based program means. The washing machine has a door latching mechanism that must be actuated to lock the access door to the closed posture prior to a cycle of operations. Before initiating a cycle a normally opened low voltage lock switch is checked by the microcontroller to insure that its contacts are open. Once the contacts of the low voltage switch are verified open, a solenoid is energized for pivoting the access door latch lever to close the contacts of the low voltage lock switch and complete a circuit path to ground. This circuit path to ground indicates to the microcontroller that the lock switch is operable and that the access door has been closed and locked. If the access door is not closed, operation of the latching mechanism will be blocked preventing closure of the contacts of the lock switch. This will prevent completion of the circuit path to ground and indicate to the microcontroller that the access door is not in a lockable position. Also, Blair et al in U.S. Pat. No. 4,866,955, disclose monitoring of a high voltage line switch by a microcontroller and preventing operation of the appliance if the switch has not cycled between open and closed posture at the completion of a cycle.
There has been no provision of a control and switch checking system for a fabric washing machine, where the electromechanical timer cannot be manually advanced, which provides for the automatic conditioning of the timer for initiating a new cycle of operations and for confirming the operability of a lid actuated switch.